docs: def _writecheck(self, zinfo):
          """Check for errors before writing a file to the archive."""
          if zinfo.filename in self.NameToInfo:
              import warnings
              warnings.warn('Duplicate name: %r' % zinfo.filename, stacklevel=3)
          if self.mode not in ('w', 'x', 'a'):
              raise RuntimeError("write() requires mode 'w', 'x', or 'a'")
          if not self.fp:
              raise RuntimeError(
                  "Attempt to write ZIP archive that was already closed")
          _check_compression(zinfo.compress_type)
          if not self._allowZip64:
              requires_zip64 = None
              if len(self.filelist) >= ZIP_FILECOUNT_LIMIT:
                  requires_zip64 = "Files count"
              elif zinfo.file_size > ZIP64_LIMIT:
                  requires_zip64 = "Filesize"
              elif zinfo.header_offset > ZIP64_LIMIT:
                  requires_zip64 = "Zipfile size"
              if requires_zip64:
                  raise LargeZipFile(requires_zip64 +
                                     " would require ZIP64 extensions")